1. Field of the Invention
This invention relates to material handling vehicle moveable into and out of a cargo carrier to unload sacked or loose material therefrom.
2. Description of the Prior Art
The unloading of sacked or bulk (loose) material from the cargo carrier in which it is transported is a timeconsuming, labor-intensive task. Moreover, it is physically taxing and difficult labor to move the cargo from its position of repose within the carrier to another location.
Additional difficulty and exertion is required in order to reach and move that portion of the cargo disposed in a relatively inacessable portion of the carrier. For example, in the case of center-door railroad boxcar, the easiest portion of the unloading task is the movement of that cargo disposed in next adjacency to the boxcar door. More difficult is the movement cargo disposed in regions of the boxcar disposed distant from the door. For the unloading of this material, it is required that laborer "turn the corner" as he both enters and exits the boxcar while unloading the material disposed at each end thereof.
Efforts to facilitate the unloading task typically include the provision of conveyors which extend from the interior of the boxcar in the vicinity of the region where the laborer is unloading cargo to the location in which the offloaded cargo will be temporarily stored. However, there are difficulties attendant upon this conveyor arrangement. As the worker advances toward the regions of the boxcar further from the door additional conveyor elements must be laid. Further, once the car is unloaded there still remains the task of rearranging the conveyor system so that the next car in the train may likewise be unloaded. It may occur that the effort required to be expended in order to rearrange the conveyor system for use in connection with the unloading of the next car vitiates the benefits provided by the conveyor system.
There are devices in the material handling art which are believed to embody attempts to mechanize or otherwise expedite the transfer of material from one position to another. Exemplary of a device utilized to transfer bulk cargo, as loose coal, from one position to another is the device shown in U.S. Pat. No. 944,438 (Holmested). This device appears to utilize a rotary turntable and a conveyor extending perpendicularly to the surface thereof. The turntable and the conveyor are both energized and material shoveled onto the forward edge of the turntable is rotated by the surface thereof to a position where it may be deflected toward a rearwardly extending conveyor by the operation of the deflector.
This device further appears to require the physical movement of the shovel (provided on the forward edge of the device) into the loose material to be conveyed or else requires the presence of a laborer in order to introduce material onto the forward edge of the turntable.
The device shown in the U.S. Pat. No. 3,127,002 (Tempe) appears to disclose a segmented wheel mounted for rotation on a surface. A scraper is provided which appears to be extendable into the mass of material to be on-loaded into the segmented wheel. Retraction of the scraper pulls material into the compartment of the wheel then presented toward the scraper blades. The wheel is then rotated so as to present the next segmented compartment thereof to the scraper so that a repeated operation of the scraper may introduce a further charge of material into the wheel. That is, it appears the movement of the wheel is dependent upon the charging of material thereinto.
Other devices in the art also appear to disclose the utilization of rotating turntables to convey material from one position to another. For example, U.S. Pat. No. 1.567,080 (Ranney) appears to disclose a device for piling or stacking sheets of material which utilizes a circular tablelike track. The device shown in the U.S. Pat. No. 3,073,431 (Davis et al.) appears to utilize a rotatable platform which is compartmentalized by partitions vertically upstanding from the surface thereof. The platform appears to be rotatable with respect to a stationary surface.
Those familiar with airline travel will also recognize that most major airports provide some form of rotational material conveyance surface by which passenger luggage may be presented for retrieval. One such luggage device introduces luggage upwardly from a vertical central section onto an inclined conelike conveyance surface which surface, as it is rotated, carries the luggage therealong.
Other devices which appear to utilize a rotating member for conveyance of material is the coal-loading device shown in U.S. Pat. No. 1.781,895 (Crawford et al.) and the bale-loading device shown in U.S. Pat. No. 2,551,427 (Ellefson). The device shown in U.S. Pat. No. 2,515,965 (Nurnberg) appears to utilize a rotating member in an apparatus for transporting bottle caps, while the device shown in U.S. Pat. No. 2,792,099 (Hefft) appears to relate to a log-feeding apparatus.
It also appears to be known to dispose a digging or trenching implement on a platform which is itself rotatable with respect to a vertical axis of the vehicle on which the implement is carried. Believed exemplary of such apparatus are those shown in U.S. Pat. Nos. 1,162,768 and 1.473,227 (both to Greenleaf), and U.S. Pat. Nos. 1,265,730 and 1,265,731 (both to Billings). Also believed to embody a disclosure of a digging implement on a platform rotatable with respect to the vehicle carrying the same are U.S. Pat. Nos. 1,277,687 and 1.446,275 (both to Billings et al.). The devices shown in U.S. Pat. No. 1,520,247 (Jacobsen) and U.S. Pat. No. 3,547,287 (Cunningham, Sr.), also appear to disclose a digging implement rotatable with respect to the apparatus on which it is mounted.
The device shown in U.S. Pat. No. 3,730,367 (Heffington) appears to be a somewhat more contemporary embodiment of the same principle and is utilized in the enviroment of a mobile refuse retriever wherein a hydraulic crane is disposed on a truck.
It is believed to be advantageous in the context of the unloading of material (whether sacked or bulk) from a cargo carrier to provide a self-propelled, moveable material handling vehicle adapted to move freely about the surface of a loading dock or railroad siding and into and out of the cargo carrier in order to expedite the unloading of material therefrom. It is also believed to be advantageous to provide such a vehicle that is appropriately controllable by a single operator. Further, advantage is believed derived if the vehicle has provided thereon a loading boom extensible and retractable along its own axis, rotatable in a horizontal plane about a vertical axis extending from the apparatus and pivotal about a horizontal axis (defined with respect with the apparatus) in a vertical plane. The motions are believed desirable in order to reach and displace material from its position of repose within the carrier.
It is also believed to be of advantage to provide the material handling vehicle with a rotatable material conveyance surface mounted such that when material is disposed thereon (as by the action of the boom and loading device) that material may be rotated to a position where it may be deflected therefrom by a suitable deflector device and onto an appropriately positioned carry-off conveyor. It is believed to be most advantageous to provide the carry-off conveyer in a position moveable with respect to the chassis of the vehicle so that the outboard end of the conveyor may always be oriented toward the entrance (door) of the cargo carrier.